"SAN JUAN, Puerto Rico -- A glowing lagoon off Puerto Rico's northeast coast has gone nearly dark and biologists on Tuesday were trying to find out why."

"Theories range from an increase in construction runoff to inclement weather to people clearing mangroves to allow larger boats into the area.

'We have been compiling data,' Carmen Guerrero, secretary of the Department of Natural Resources, said in a phone interview as she headed toward Las Cabezas de San Juan Nature Reserve with a team of scientists to investigate the problem. 'There are a lot of factors that could be at play.'"

Danica Coto reports for the Associated Press November 19, 2013. [2]